Although the development of light emitting diodes has in many ways revolutionized the lighting industry, some of the characteristics of light emitting diodes have presented challenges, some of which have not yet been fully met. Efforts have been ongoing to develop lighting devices that are improved, e.g., with respect to energy efficiency, color rendering index (CRI Ra), contrast, efficacy (lm/W), and/or duration of service. In addition, efforts have been ongoing to develop lighting devices that include LED's instead of other forms of light emitters. Ideally, the cost of such lighting devices should be comparable with traditional incandescent lighting to facilitate their acceptance and utilization.
LED light bulbs find application in indoor and outdoor applications, and one particular application of utilizing an LED light bulb is to replace white incandescent light bulbs. The conventional approach utilizing LEDs in light bulbs is to arrange the LEDs on a PCB or other substrate so as to project their light directly towards a lens, such as a dome, diffuser, or a cover.
Current configurations of LED light bulbs, where the LED's and additional circuitry, for example, thermal compensation circuits, are positioned on, or integral with the same board and in the same plane as LED circuitry has limitations in productivity and production flexibility.